

var ArrayCtor = typeof Float32Array === 'undefined' ? Array : Float32Array;
/**
         * @typedef {Float32Array|Array.<number>} Vector2
         */
/**
         * 二维向量类
         * @exports zrender/tool/vector
         */
var vector = {
    /**
             * 创建一个向量
             * @param {number} [x=0]
             * @param {number} [y=0]
             * @return {Vector2}
             */
    create: function (x, y) {
        var out = new ArrayCtor(2);
        out[0] = x || 0;
        out[1] = y || 0;
        return out;
    },
    /**
             * 复制向量数据
             * @param {Vector2} out
             * @param {Vector2} v
             * @return {Vector2}
             */
    copy: function (out, v) {
        out[0] = v[0];
        out[1] = v[1];
        return out;
    },
    /**
             * 克隆一个向量
             * @param {Vector2} v
             * @return {Vector2}
             */
    clone: function (v) {
        var out = new ArrayCtor(2);
        out[0] = v[0];
        out[1] = v[1];
        return out;
    },
    /**
             * 设置向量的两个项
             * @param {Vector2} out
             * @param {number} a
             * @param {number} b
             * @return {Vector2} 结果
             */
    set: function (out, a, b) {
        out[0] = a;
        out[1] = b;
        return out;
    },
    /**
             * 向量相加
             * @param {Vector2} out
             * @param {Vector2} v1
             * @param {Vector2} v2
             */
    add: function (out, v1, v2) {
        out[0] = v1[0] + v2[0];
        out[1] = v1[1] + v2[1];
        return out;
    },
    /**
             * 向量缩放后相加
             * @param {Vector2} out
             * @param {Vector2} v1
             * @param {Vector2} v2
             * @param {number} a
             */
    scaleAndAdd: function (out, v1, v2, a) {
        out[0] = v1[0] + v2[0] * a;
        out[1] = v1[1] + v2[1] * a;
        return out;
    },
    /**
             * 向量相减
             * @param {Vector2} out
             * @param {Vector2} v1
             * @param {Vector2} v2
             */
    sub: function (out, v1, v2) {
        out[0] = v1[0] - v2[0];
        out[1] = v1[1] - v2[1];
        return out;
    },
    /**
             * 向量长度
             * @param {Vector2} v
             * @return {number}
             */
    len: function (v) {
        return Math.sqrt(this.lenSquare(v));
    },
    /**
             * 向量长度平方
             * @param {Vector2} v
             * @return {number}
             */
    lenSquare: function (v) {
        return v[0] * v[0] + v[1] * v[1];
    },
    /**
             * 向量乘法
             * @param {Vector2} out
             * @param {Vector2} v1
             * @param {Vector2} v2
             */
    mul: function (out, v1, v2) {
        out[0] = v1[0] * v2[0];
        out[1] = v1[1] * v2[1];
        return out;
    },
    /**
             * 向量除法
             * @param {Vector2} out
             * @param {Vector2} v1
             * @param {Vector2} v2
             */
    div: function (out, v1, v2) {
        out[0] = v1[0] / v2[0];
        out[1] = v1[1] / v2[1];
        return out;
    },
    /**
             * 向量点乘
             * @param {Vector2} v1
             * @param {Vector2} v2
             * @return {number}
             */
    dot: function (v1, v2) {
        return v1[0] * v2[0] + v1[1] * v2[1];
    },
    /**
             * 向量缩放
             * @param {Vector2} out
             * @param {Vector2} v
             * @param {number} s
             */
    scale: function (out, v, s) {
        out[0] = v[0] * s;
        out[1] = v[1] * s;
        return out;
    },
    /**
             * 向量归一化
             * @param {Vector2} out
             * @param {Vector2} v
             */
    normalize: function (out, v) {
        var d = vector.len(v);
        if (d === 0) {
            out[0] = 0;
            out[1] = 0;
        } else {
            out[0] = v[0] / d;
            out[1] = v[1] / d;
        }
        return out;
    },
    /**
             * 计算向量间距离
             * @param {Vector2} v1
             * @param {Vector2} v2
             * @return {number}
             */
    distance: function (v1, v2) {
        return Math.sqrt((v1[0] - v2[0]) * (v1[0] - v2[0]) + (v1[1] - v2[1]) * (v1[1] - v2[1]));
    },
    /**
             * 向量距离平方
             * @param {Vector2} v1
             * @param {Vector2} v2
             * @return {number}
             */
    distanceSquare: function (v1, v2) {
        return (v1[0] - v2[0]) * (v1[0] - v2[0]) + (v1[1] - v2[1]) * (v1[1] - v2[1]);
    },
    /**
             * 求负向量
             * @param {Vector2} out
             * @param {Vector2} v
             */
    negate: function (out, v) {
        out[0] = -v[0];
        out[1] = -v[1];
        return out;
    },
    /**
             * 插值两个点
             * @param {Vector2} out
             * @param {Vector2} v1
             * @param {Vector2} v2
             * @param {number} t
             */
    lerp: function (out, v1, v2, t) {
        // var ax = v1[0];
        // var ay = v1[1];
        out[0] = v1[0] + t * (v2[0] - v1[0]);
        out[1] = v1[1] + t * (v2[1] - v1[1]);
        return out;
    },
    /**
             * 矩阵左乘向量
             * @param {Vector2} out
             * @param {Vector2} v
             * @param {Vector2} m
             */
    applyTransform: function (out, v, m) {
        var x = v[0];
        var y = v[1];
        out[0] = m[0] * x + m[2] * y + m[4];
        out[1] = m[1] * x + m[3] * y + m[5];
        return out;
    },
    /**
             * 求两个向量最小值
             * @param  {Vector2} out
             * @param  {Vector2} v1
             * @param  {Vector2} v2
             */
    min: function (out, v1, v2) {
        out[0] = Math.min(v1[0], v2[0]);
        out[1] = Math.min(v1[1], v2[1]);
        return out;
    },
    /**
             * 求两个向量最大值
             * @param  {Vector2} out
             * @param  {Vector2} v1
             * @param  {Vector2} v2
             */
    max: function (out, v1, v2) {
        out[0] = Math.max(v1[0], v2[0]);
        out[1] = Math.max(v1[1], v2[1]);
        return out;
    }
};
vector.length = vector.len;
vector.lengthSquare = vector.lenSquare;
vector.dist = vector.distance;
vector.distSquare = vector.distanceSquare;
module.exports = vector || module.exports;;